The Lethal Hero: Green Venom
by EggsOnToast
Summary: Izuku always wanted a quirk. Despite All Might promising to train him to be a quirkless hero, Midoriya wished he had a superpower of his own. So when a black slime alien offers him amazing powers in exchange for a regular dose of dark chocolate and liver, a partnership is made. Now Izuku can finally achieve his dreams. If he can keep his kraving for brains under control though.


The black, swarming goop was at death's doorstep. It was sentient and conscious when the experiments began. When the torture started. For weeks, it experienced nothing but pure agony. The heat. The deafening machines. They were withering its health slowly. They didn't even know they were killing it because to them, it was just another thing to dissect. The worst part though, it was hungry. No. **Starving**.

Eating was how it regenerated. Eating is what made it strong. Just a morsel of meat would last it another week. But these ignorant scientists didn't even know what to feed it.

They were currently exposing it to UV light, the heat from the bulbs unintentionally searing it alive. '**These absolute idiots! Do they actually believe I sustain through photosynthesis? Do I look like a plant? I. Need. MEAT DAMNIT**,' The black goo monologued.

"I think we've finally made a breakthrough with this thing!" It heard one of the scientists exclaimed excitedly. '**NO. Absolutely not! DAMN YOU PEOPLE.**'

"Great job. Perhaps we've done enough for today," A scientist said, shutting the UV lights off. Immediately, the black slime was relieved from its torment. "Can't overwork the little guy, it's got to rest. Ain't that right Pudding?"

**'Call me that pet name again and I will tear your eyes out for a snack vermin**.'

"You do have a point. Ah man, feeding the slime got me famished. Want to go out and get ramen?"

**'Yes, please leave me alone. I would prefer dying peacefully with no one around**."

"Sounds good to me. I don't wanna be around middle schoolers when they get here," one said shutting the lights in the control room. "See ya Oobleck." With that closing statement, the room fell silent and became completely vacant except for the lab experiment.

The black slime began to weakly slug around. It knew full well that its confinement was well made, lacking any faults in the walls or ground. '**I just need a host and I'll survive. Any vessel would suffice to avoid death. If only I could find some way out**.'

For what felt like hours, the small and weakened slime alien crawled around the room, looking for any possible place it could evade. At first, it was a normal routine it did, often ending with no luck. But this time, it was a last-ditch effort. However, it seemed as if it was going to end the same way it always did again.

'**Shit, I am actually going to die. This is really it, how I go out. How pathetic**...' It sadly told itself. The whole situation seemed absolutely hopeless.

That was until it sensed something. Faint radioactivity. It was familiar with what the scientist usually exposed it to, so it knew full well that this one was different.

Sensing its surroundings, it finally found the source of the radioactivity. There was a spider. Just up on the ceiling.

**'YES, HOST!**' It cheered to itself.

It was quite large, with red and blue designs covering it. Of course, it wouldn't last very long as a host, perhaps for a solid five minutes before it crumpled due to it being weak. But it couldn't be picky right now. What mattered was survival.

The black slime slowly and quietly made its way up to the roof where the spider was. When it finally closes the distance between them, the symbiote quickly made its move, latching onto the spider, seeping into its small body as it struggled with its assailant. It proved futile though, as in a matter of seconds, the spider's once red and blue color scheme transformed into new green, white, and black design.

**'Yes, I live on. However, something appears to be off about this thing**.' It couldn't point it out at first, but the black goop felt something powerful emitting off the spider. However, going through its genetic structure, the black goo found what was up. **'Interesting, the arachnid has been genetically modified, explaining its rather high emission of radioactivity. But that's no matter**…'

Through its now eight eyes, it was able to make out the area. '**If it got in, then I can get out**.'

Wasting no time, it crawled around the testing room. The goo had searched just about every inch of the room before even meeting the spider. It had to have come through a secret hole or crack. 'Have to hurry. Only three minutes till this body gives out and I'll be hostless again'

The black sludge couldn't mindlessly search for its escape anymore. It had to be smart about its approach or else he was going to waste more time. It began scanning the small room once more, taking account into every detail, or more accurately, lack thereof. After all, it was just a blank white room. Nothing was sticking out until something caught its eye, or this case right now, eyes.

It was very easy to miss, almost invisible. But with a more detailed second look, the symbiote got excited. There was a small sliver between the roof and the wall. Big enough for a spider to crawl through.

'**Huh, I knew it. If there is one thing I know about humans is that they are not perfect. Neither are their creations**,' the symbiote chuckle happily to itself as it crawled toward its path to freedom. Squeezing itself through, the refreshing sight of dust, old wood, and electrical wires filled its vision.

'**Finally, out of that accursed confinement, all I need now is a new host,'** It began to feel its small body growing weaker, certainly dying from it assimilating with the arachnid. It had approximately 2 minutes left with it and the host would be dead. And it wasn't sure if it could go on any longer without a host.

* * *

Izuku Midoriya was in both extremes if being excited and exhausted. Ecstatic about the science tour and their new data from quirk testing and also micro sleeping halfway through the school day from All Might's intense training regimen.

The place his middle school had visited was the Saitama STEM and Future Developments Center, an absolute marvel and privilege to attend. From the latest developing medicine for combating chronic illnesses to just plain quirk experimentation was all here.

And Midoriya was just half awake for it.

'Damn it, I need to stay focused. This place has great information and interesting development that I have to note of,' his studious side was scolding him to wake up. 'But, I haven't had a goodnight's rest in weeks as well any breaks from training!' His tired side complained.

His internal battle continued as their tour guide lead his middle school class around the facility. Each exhibit showcased some incredible creation, one example being a powerful battery that could form armor with nanoparticles, while another being what looked like Karem Rider suit that could shrink and talk to ants.

Despite such amazing things presented to him, Midoriya was still extremely groggy. Now it was annoying him, having to practically kick himself to stay awake.

This wasn't as big as a problem as it was now. It started 5 months ago really when his idol told him the words that changed his life forever.

_The sun was setting as the wind picked up, carrying cherry blossom petals through the cool air. His hero, soon would-be mentor, stood in front of him in his skeletal, and weak form. Izuku was already beginning to have tears fill his eyes as Yagi Toshinori, All Might, THE Number One Hero spoke to him, "That's what happened to you too right? Your legs moved on their own?"_

_Izuku merely let out an inaudible 'yes' as a response as he was losing a grip on his emotions._

_All Might smiled and then said it. "Young Midoriya, you can become a hero!"_

_The waterworks were then released and Midoriya was overwhelmed. Happiness, sadness, satisfaction, swelled his heart with raw emotion._

_"And young man, I will be willing to train you to become the best hero you can possibly be. It is my thanks for your help in realizing what true heroism is again. Do you accept?"_

_Still emotional and sobbing, Midoriya mustered the best formal response to such an offer the best he could. "Yes! Teach me how to be strong All Might!"_

So began Midoriya's trip through hell and he was training not stop. Muscle conditioning had taken a massive toll on him physically and mentally. Clearing massive junk at the beach was like experiencing death repeatedly, he could feel ready to collapse from fatigue every post-training secession.

'To think I have to keep this up for another 5 months, this will be an ultimate test of my willpower. I just hope I'm not dead yet by the end of it.' the green-haired boy muttered to himself.

"Wake up and shut it with your muttering you creepy ass nerd or I'll do it for you," a certain spiky-haired, ash-blonde kid threatened as he walked past Midoriya angrily. "I don't know why you're even training that hard to get U.A. without a quirk but I'm not the one who decides how you waste your time."

Katsuki Bakugou. He was never mean when they were kids. They were once best friends in fact. But as time went on, their friendship would take a swan dive off a roof and would be left in ruins. "Sorry, my bad," he apologized weakly. 'That bastard I already have my own demons Kacchan, I don't need you to be another…' Midoriya angrily ranted in his head.

The thing is, there would be moments where Izuku did feel like giving up. Whenever he looked at things realistically, he couldn't help but feel depressed. He was still quirkless. And he could only get as strong as humanly possible. And without a quirk to back him up, he was at a severe disadvantage. No amount of strength training or fighting skill was going to be practical against a Kaiju-sized villain. And without a quirk, he certainly couldn't become the number one hero.

It was thoughts like this that haunted Midoriya. That made him question whether or not if all of his hard work was just a waste of time as Kacchan said. Being powerless was the biggest demon he faced throughout his whole life. Because the truth was, **Izuku Midoriya always wanted a quirk**.

"Alright, now onward to the next exhibit!" The cheery voice of the tour guide interrupted his conscious.

Realizing he hadn't been paying attention at all to the lecture, he felt himself get frustrated. Shaking his head and trying to clear it, he shoved such toxic thoughts into the back of his mind again and moved on. Harping on the worst was not going to happen on a day as cool as this. Unbeknownst to him, a certain black, green, and white spider had crawled out of a vent on top of him.

'**I'm finally out, but with only less than a minute left with this disposable host! I need to switch now**!' It said in a panic. With a glance of its surroundings, it saw a group of young humans walking away from where it was. The radioactive spider's body was becoming even slower and weaker to control and the symbiote couldn't afford to be exposed again. It needed a new host now.

The nearest human closest to it was a green-haired boy, just directly underneath him. It began to stalk the kid, crawling upside down on the ceiling and trying to keep up with his pace as he walked with his group.

**' Only 20 seconds left! Stupid boy, hold stil**l!' The sludge said to itself frustrated.

Midoriya's group finally stopped at the new exhibit that was based on genetic modification through radiation. 'Now's my chance!' The alien said. Falling onto the boy's right sleeve, the symbiote controlled spider made its way as fast as it could toward Midoriya's hand.

'Did something drop on me?' The green-haired boy swore he felt. He looked toward his right arm and gasped loudly as it was already too late. A large spider had reached his hand. Before he could swat it away, it clamped down on his flesh with its venomous fangs.

Feeling nothing more than a hard pinch, he brushed off the small sharp pain and flicked the small creature off his hand.

'Sheesh, I thought for a pristine science facility they would be bug-free,' muttered to himself. Checking his hand he saw no signs of swelling and felt no intense pain.

'I guess it was just a harmless one. Most spiders aren't even venomous anyways. Lucky me.'

There, he began giving his attention back to the lecture again. But this time, he was giving it his full focus. "That's amazing what they did. Who knew we could manipulate insects like that just through simple..," Midoriya began to mutter.

"Great, the nerd is on a roll again. I guess he finally woke up," Bakugou commented, clearly annoyed. Midoriya, having overheard his former friends insult, realized that himself just now as well, his grogginess was completely gone. Smiling now that his head was back in the game, he continued to listen carefully and soak up any info they presented. "I guess all I needed was a scare to wake me up," he said happily to himself.

And a little away from the group and where Izuku was standing laid a dead red and blue spider...

* * *

Having been an hour after Midoriya's trip, he had returned to his school which had ended for them for the day and was making his daily walk home. More accurately, he was practically skipping his way home, as he was quite content with how things turn out. The field trip was a blast for Izuku, opening his eyes to the new and endless possibilities of the future. Plus he wasn't even picked on that much today. He could easily say his day was turning for the better than how he woke up this morning.

GROWL

That was until his stomach began to scream for food.

'Huh, I swore I had a snack on the bus ride home,' Midoriya remembered. Then a sharp jolt of pain suddenly resonated throughout his body. 'Ouch, what is up with me? I was fine a second ago. Was it something I ate?'

The closer he got home, the worse it felt after that. He felt sick, concluding he was catching a cold, and at a fast rate too. It was strange how it was happening so suddenly. It didn't feel like a normal fever either, as it wasn't a usual tired and aching that a cold typically brought. No, fevers shouldn't be making him feel as if all of his insides were being reorganized.

His already sore muscles now felt like they were on fire. His head felt lightheaded and as if it was on a merry go round. As his apartment complex came into view, he noticed how sweaty his whole body was, his collar soaked. He felt fatigued once again like from earlier, this time feeling as if he ran a 5k.

Reaching the entrance, Midoriya made his way up the three stories worth of stairs, causing him to feel like he was climbing Everest and his hunger became more aggressive.

'Man, I could eat a deer. Huh, now that I think about it, that sounds pretty delicious. Tasty, tender, raw veniso- wait... Raw?! Why am I craving raw meat all of sudden!' He thought to himself. Finally, his journey home was over as he was at his front door. Fumbling for his keys, he struggled to aim his house key into the keyhole. Finally slipping it in, he twisted it and was in, noticing his apartment was dark.

Retrieving his key into his pocket and closing the door behind him, he looked around a bit more. His mother wasn't home, most likely grocery shopping he assumed, and dinner probably wasn't going to be in another three hours. 'Man, I was hoping mom was home to make me something. Guess I'll have to do it myself.' Feeling sick and hungry, Midoriya turned on the kitchen light whipped out the best snack for a situation like this, a pack of chicken-flavored instant ramen straight from his pantry.

Getting a pot of and filling it halfway with water, he set the pot on the stovetop at medium heat. However, his growling, aching stomach, and his sore body were torture.

'Man, if my fever doesn't get better, All Might's gonna cancel training today. What is up with me?' Midoriya worriedly thought to himself, before casually taking a bite of the uncooked ramen. Crunching on the brittle noodles, it took a second for him to realize what he had just done. Swallowing what he bit off, he scolded himself for being impatient and plopped the bitten ramen noodles into his boiling pot.

As his noodles cooked, he entered the comfort of his room and tore off his sweaty school uniform, leaving him in just All Might boxers, feeling cooler as his A/C remedied his burning body. Glancing at the mirror, he took note that he was skinny, though not a twig-like he used to be 5 months prior. To simply put, he was definitely a work in progress for now.

But in his current condition, there was no way he could train as he continued to feel very ill and tired. All Might would for sure notice and he'd be sent home, wasting both of their times. He needed to rest. Gravitating toward his bed, he collapsed onto his sheets. Yawning and feeling his eyes beginning to close, Midoriya made a mental note before drifting. '5 minutes, just 5 minutes. And then back to work…'

…

…

…

…

"**IZUKU**!" a demonic voice spoke.

"AHH!" Midoriya jolted from his sleeping position. His eyes were now wide open, fully awake and scanning furiously around his room. However, he couldn't find any possible source where it came from. Now a little scared, he tried to brush it off as a hallucination induced by his exhaustion. "Huh, I guess it was nothing," the green-haired boy told himself. He looked at his alarm clock, scolding himself for sleeping… only for five minutes. He had woken up exactly when he needed to. How fortunate.

Hearing the violent bubbling coming from the kitchen, Midoriya cursed himself for leaving the stove on carelessly. He quickly got out of bed shut the stovetop off. Looking into the pot, he was saddened by the sight of overcooked noodles. However, he wasn't going to let food go to waste.

'Well, at least I can say my nap helped. I feel way better than a couple of minutes ago. I swore I was sick. I guess training will continue and I should be headed to the beach soon. I can't leave All Might waiting.' He thought to himself as he poured his meal into a bowl. 'Though I gotta eat something before I go. I'm so hungry.'

Wanting to be changed, he walked back to his room and went for his drawer, that is until he realized something after he passed the mirror. He went back and his jaw dropped. He was freaking jacked.

Abs. Biceps. Watermelon-crushing thighs. He had it all. Flexing a bit only made his roaring muscles even more defined. 'I look incredible! But this makes no sense! How did I become so fit in five minutes? I have to be dreaming!'

Pinching himself, he was able to confirm he was indeed awake. From suddenly getting sick to suddenly feeling better and now attaining the body of an athlete from a nap, this had to be his strangest day yet. And there was no logical explanation for it. There was no way his day could get any weirder.

Then, a black, slimy head popped out of his shoulder and started speaking to him "**It's a pleasure meeting you Izuku Midoriya. My name is Venom**."

And that's when Izuku screamed.


End file.
